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Insects have a highly sensitive sense of smell. Extremely low concentrations of odor molecules in the air are sufficient to be detected by receptor neurons on their antennae. Specific proteins, so-called receptor proteins, expressed in these neurons recognize the odors. The odor molecules bind to the receptors and produce chemical and electrical signals that are processed in the insect brain and eventually affect the insect's behavior.
Apart from the receptors, further proteins involved in olfaction, including enzymes and chemosensory proteins, come into play. Based on these molecular principles, all insects follow their innate and elementary survival formula: finding food, recognizing mates, and − in case of females − identifying adequate oviposition sites that guarantee nutritious and easily digestible food for their offspring.
Moths (Lepidotera) are popular research objects in addition to fruit flies. The genome of the silkworm Bombyx mori has been fully sequenced; however, this insect has been domesticated by humans for thousands of years, therefore its native conspecifics cannot be found anymore. On the other hand, the "habits" of the tobacco hornworm Manduca sexta, a moth species native to North America, have been the subject of intense physiological investigations to study the insect olfactory system, and recently also because its host plant, wild tobacco Nicotiana attenuata, has advanced to an important model plant in ecological research.
Genetic analysis of the Manduca sexta antennae closes a gap in the search after the insect's odor-directed behavior: The release of stress-induced odor molecules by tobacco plants is well studied, as is the pollination of the flowers by the moths. "But how does the plant odor metaphorically speaking −
|Contact: Bill S. Hansson|
Max Planck Institute for Chemical Ecology